1. Field of the Invention
The present invention relates to a liquid crystal light valve and a method for making the liquid crystal light valve thereof, which is an especial liquid crystal light valve adapted for low voltage operation and considerable energy conservation.
2. Description of Related Art
Polymer-dispersed liquid crystal (PDLC) is currently the most dominating application of a scattering light valve, and the operating voltage needed for it ranges approximately between 60 to 70 volts. For the scattering light valve, the liquid crystal light valve is maintained in a light-scattering state so that the light is blocked when there is no interference of externally applied voltage. But when an external voltage is applied on the liquid crystal light valve, the liquid crystal light valve will turn to appear transparent and allow the light to pass through.
For details on the use of liquid crystal light valve, please refer to FIG. 1A-FIG. 1C, which show perspective views of use of liquid crystal light valve. As shown in FIG. 1A, the light cannot pass through the liquid crystal light valve 101 when no external operating voltage is applied onto the liquid crystal light valve 101. Under this condition, it is not possible to see any object through the liquid crystal light valve 101. On the other hand, when an external voltage is applied (e.g. by applying an operating voltage of 30 volts), the liquid crystal light valve 101 will begin to show light transmission. As shown in FIG. 1B, when part of light passes through a liquid crystal light valve 101, the view of the object behind the liquid crystal light valve 101 can be roughly seen.
Moreover, when the operating voltage is increased to about 60˜70 volts, the light transmittance of liquid crystal light valve 101 will be correspondingly increased to its maximum level. Under the situation as shown in FIG. 1C, the liquid crystal light valve 101 can permit more light to pass through, and making the view of the object at the rear of the liquid crystal light valve 101 more clear to be seen.
However, there are still many drawbacks can be found in the abovementioned known liquid crystal light valve 101. For example, liquid crystal light valve 101 of the known art would require exceptionally high operating voltage (for instance, 60 to 70 volts for operating voltage, as described), such undertaking would mean consumption of a great deal of energy to keep the liquid crystal light valve 101 of the known art running. Furthermore, known liquid crystal light valve 101 requires a long response time. That is, when the external operating voltage is adjusted from its original state, the light transmittance of the liquid crystal light valve 101 will not be able to response immediately to the operating voltage that has changed, and adjust itself accordingly. In addition to this, the known liquid crystal light valve 101 also faces a viewing angle related problem, in which the light valve is not suitable for all viewing angels.
In view of the above, although liquid crystal light valve has excellent properties to offer, it is still restricted by numerous drawbacks and cannot find public popularity. As a result, there is a need in the industry for a novel liquid crystal light valve, one such that could improve on the particular disadvantages so as to make the liquid crystal light valve more acceptable for use in application.